The post-Ottoman period witnessed the division of much of the Middle East into new states, and various institutions worked to cement the imagination of Iraqi, Syrian, or Turkish identities to match this new map. But the division of the region occurred on another level, one less well-studied. Even figures as minor as locusts fell into the dragnet of identity, and their mobility made fitting them into the region’s new borders both imperative and particularly challenging. Especially in the Jazira—the borderlands region stretching across Iraq, Syria, and Turkey—the provenance of the insects became a major topic of debate between government officials during the 1920s and 1930s. Because of the insects’ mobility, they instigated these questions of origins. In the process, officials used language much like that applied to humans to describe the creatures, with Turkish officials wondering, for example, whether locusts invading their territories had been born in Syria. British officials in Iraq even went so far as to suggest that the species of locust in their domains was unique, and seeing as the range of the “Iraq locust” only stretched some 40 miles, it could hardly be blamed for depredations in Turkey. In other words, the impetus to separate the region’s connected geography was so great that British officials invented their own species of locust, as if an insect would respect any borders, let alone northwestern Iraq’s famously jagged ones. The interwar period may have witnessed the birth of new institutions devoted to international cooperation, but little collaboration took place with regard to locusts. Locusts thus foreground questions of scale in an ecology stretching across borders. Ultimately, officials responded to the shared dilemma through the technological innovation of sodium arsenate, which increasingly covered the Jazira, no matter the country, and no matter the disputes between the countries. Relying on materials in Arabic, English, French, and Turkish, this paper builds on Cyrus Schayegh’s work, which suggests how the division of the post-Ottoman Middle East also in many ways brought these countries together. Locust management offers one glimpse of these dynamics, but it also signals the way that connection occurred simultaneously with disavowal of that same connection. The paper thus raises questions about mobility, technology, and state authority in the post-Ottoman period from an environmental perspective to trace the territorial dimensions of post-Ottoman regimes in the region.